The sensory nerves of the teeth are subject to stimuli from various sources, including heat, cold, sugars, hypertonic solutions and the like. Usually, these various stimuli do not disturb the normal functioning of the dental sensory nerves. However, when the sensory nerves become more easily excitable, for example, because of dental erosion, gum recession, exposure of the dentin or other causes, the teeth are more sensitive than usual to stimuli, resulting in distress and pain. When such an elevation of sensory nerve activity occurs, it is necessary to reduce the dental sensory nerve activity and to desensitize the hypersensitive dentin in order to reduce or relieve the pain. One way of accomplishing this result is to apply to the dentin an effective amount of a substance which can reduce sensory nerve activity and desensitize the hypersensitive dentin.
Numerous methods for desensitizing hypersensitive teeth have been described and a number of commercial products exist for this purpose. However, none of these methods involve the potassium salts of the present invention.
A composition containing a mixture of 12.5 grams of potassium carbonate and 2.5 grams of anhydrous sodium carbonate has been described as useful for the treatment of hypersensitive dentin, Accepted Dental Remedies, Seventh Edition, page 187 (1941). Hodosh, U.S. Pat. No. 3,863,006 (1975) discloses the use of nitrate salts, including potassium nitrate, for desensitizing hypersensitive teeth and dentin. Hodosh also discloses that other potassium salts were tried but none were as effective as the nitrate (col. 1, lines 62-64). Pashley, et al., U.S. Pat. No. 4,057,621 (1977) disclose the use of compositions containing oxalate salts, including potassium oxalate, for desensitizing hypersensitive dentin and teeth. Svajda, U.S. Pat. No. 3,689,636 (1972) discloses the use of compositions for desensitizing sensitive teeth containing a mixture of chloride salts of calcium, magnesium, sodium and potassium, preferably each being present in equal parts of saturated aqueous solutions. However, Svajda neither teaches or suggests that any one component of the mixture may be employed alone or that any one component provides greater desensitizing action than another component. Specifically, Svajda neither teaches or suggests that potassium chloride is particularly useful for desensitizing sensitive teeth and dentin.
It has now been unexpectedly found that the application of potassium bicarbonate or potassium chloride in effective amounts to the surface of the dentin of a subject's hypersensitive teeth reduces sensory nerve activity and desensitizes hypersensitive dentin to a degree not previously achieved with other methods of treatment. When applied at equal concentrations potassium bicarbonate, in particular, yields better results than other sensory nerve activity inhibitors or dentin desensitizers.